The invention concerns an improved system bearing on a small arm with a mounting mechanism for a barrel in a barrel receiver which functions together with a breech bolt.
There are known guns by which the barrel can be exchanged for the firing of different calibers. With such weapons, usually the barrel, locking assembly and the trigger assembly, together with the system bearing block, comprise a system capable of firing.
In one known design, the barrel is exchangeable by loosening a dual screw fitting. The one screw fitting engages into the sight foot, the other screw fitting into the locking assembly into which the cartridge bearing of the barrel is inserted. By this manner of anchoring, a more or less complete stripping of the gun is necessary, such that a change of barrel for this known gun makes large scale disassembly and assembly necessary.
Thus, the task underlying the invention is to submit a system which enables changing from one caliber group to another using simple and economical construction.
The task is solved according to invention in that the barrel is clamped in the barrel bed of the barrel receiver by means of a wedge-locking mechanism. This wedge-locking mechanism can be released or tightened without disassembly of further components such that a simple and expeditious exchange is guaranteed. A specific design form consists of the wedge-locking mechanism being an eccentrically functioning tension bolt arrangement designed between the barrel and barrel receiver.
The bolt can be eccentrically designed with advantage.
This tension bolt is twistable and is received in a bore hole running transverse to the direction of the barrel, which bore hole is formed partly on the external circumference of the barrel and partly in the barrel bed of the barrel receiver. The wedging is applied by a simple twisting of the bolt whereby an essential force component is directed against the back stopping face of the barrel bed.
It is additionally advantageous that the bolt centers lie in the barrel receiver. Through this measure, it is achieved that the effective force on the barrel can be supported on the barrel receiver.
In this, it is preferred that the centers lie in a common plane Z.
The diameter of the borings for the tension bolt can be advantageously of different sizes, whereby the diameter in the barrel can be selected larger than the diameter of the bore hole in the barrel bed. One achieves an especially good eccentric effect by this.
A flat on the tension bolt is advantageously designed by which, with twisting the bolt, an eccentric-like effect is applied to the barrel.
The advantage of this is that for a gun with a system bearing block the tension bolt is secured by means of a holding screw which is passed through the system bearing block and is thus reachable. The holding screw presses advantageously onto the flat of the tension bolt by this.
It is especially advantageous if the depth H of the stopping face is greater than that of the tension height of the boring in the barrel.
The barrel receiver exhibits an inset projection in the region of the tension bolt assembly, which is inserted into an inset recess furnished in the system bearing block and secured by means of a screw.
The system bearing block advantageously exhibits essentially a T-form in longitudinal section, whereby are arranged: In the perpendicular bar, the receiver for the magazine; the wedge-locking mechanism for the barrel in the front part of the bar; and, in the rear part of the transverse bar, the trigger mechanism. The advantage of this is that the section of the bore hold formed in the barrel is part of a cylindrical boring and the section formed in the barrel bed is likewise part of a cylindrical boring whose midpoint in reference to the midpoint of the bore hole, partially in the barrel, is displaced by a specific amount toward the back in the direction of the breech. In this manner, a twisting of the tension bolt leads to a displacement of the barrel, or to a force effect on the barrel, respectively, in the direction of the stopping face in the barrel bed.
In an advantageous design it is provided that a stopping face is arranged on the tension bolt. As the holding screw is advantageously guided through the system bearing block and also through the stock, external access is possible without difficulty.
The holding screw presses against the stopping face of the tension bolt in an advantageous manner.
In an alternative design, it is intended that transverse to the lengthwise direction of the barrel is at least one, in cross section essentially rectangular recess formed in part in the barrel, in part in the barrel receiver, for receiving at least one correspondingly formed wedge.
With this, the recess in the barrel indicates a further distance from the end stopping face in the barrel bed than the recess in the receiver. Through this measure it is ensured that, with an inserted wedge in functional position, the barrel is pressed against the stopping face.
The advantage of this is that at least a single wedge is tightenable, such that the tight position of the wedge can be fixed. As a consequence of such measures, a releasing of the wedge is not to be feared even with a multiple shots.
As a tightening mechanism, it can advantageously be provided that a screw, directly or indirectly supported by the barrel receiver, is arranged on the tapered end of the wedge. This screw assembly, for example, consists of a screw which is screwed into a threaded hole, brought into the small face of the wedge in the longitudinal direction, whereby the head of the screw or an interposing washer shim is supported by the barrel receiver wall.
It is especially advantageous for reasons of symmetry if two directionally opposed wedges are provided. These wedges can be insert either in a common recess with corresponding wedge surfaces directly abutting, or they can, however, also lie respectively in a separate recess.
With the next design form, a second locking mechanism, placed at a distance from the wedge-locking mechanism, can be provided as a supplemental locking mechanism which tightens the barrel/receiver unit with reference to the system bearing block. Through this, additional security is given so that a reliable barrel seating is guaranteed which also leads to, with the greatest forces which occur, for example, during the shooting of magnum ammunition, a constant shooting performance under this shooting load.
The supplemental locking mechanism advantageously consists of a pressure screw that is screwed into a threaded hole in the system bearing block, and, leading through a bore hole in the receiver, presses against the barrel. For this, it is advantageous to make, on the barrel, a recess having a pressure surface for the pressure screw.
With the use of a system bearing block it is advantageous to provide a chamber for the holding bolt of a magazine. Advantageously, the holding bolt is arranged on the side of the magazine lying opposite the trigger guard, by which it engages the face of the magazine. The holding bolt can be advantageously furnished with a spring-loaded holding pin which exhibits a face side catch which combines with a corresponding notch in the magazine.
What is advantageous with this is that at least one inclined running ramp is provided in the transverse direction on the holding bolt which works together with a corresponding spring-loaded actuation button exhibiting a corresponding ramp for the purpose of forward and backward movement of the holding bolt. By this type of an arrangement of the holding bolt on the face side of the magazine, a positive motion sequence during exchange of the magazine can be achieved. During actuation of the holding bolt, the half-opened hand is located beneath the magazine while simultaneously the thumb and index finger can release it through pressing together by means of the actuation button. At release, the magazine falls into the opened hand such that no repeated grasping about is necessary.
The firing of different ammunition can make it necessary that the firing pin path be varied. For this, it is advantageous that in coordination with corresponding exchange barrels, different firing pin nut designs are provided whose pressure surface in the longitudinal direction are arranged at respectively different positions. Special design of these firing pin nuts, can be provide that the pressure surface is adjustably held. This movability, in the simplest case, can be the end surface of an adjusting screw. In a special design, however, it can be planned that the pressure surface is formed on an adjustable sliding pressure block which is movably held on the firing pin nut.